Women whose ovaries are stimulated to produce extra eggs for in vitro fertilization have an increased risk of ovarian cancer later in life, according to research published in the journal Human Reproduction.

The long-term risk for ovarian tumors is twice as high among women who undergo stimulation for in vitro fertilization compared with women who don’t undergo such treatments to boost fertility, according to the study, which was conducted at the Netherlands Cancer Institute in Amsterdam.

Ovarian cancer is the eighth-most commonly reported tumor type, accounting for 3.7 percent of all female cancer cases, according to a statement from the journal, which is published monthly by the European Society of Human Reproduction and Embryology. More than 140,000 women died from the disease in 2008 worldwide.

“If we find out that women who receive several IVF cycles or large doses of ovarian-stimulating drugs are at a greater risk of ovarian cancer, then these women would need to be informed about these risks when continuing IVF treatment,” said lead researcher Professor Flora van Leeuwen in the statement. Patients may be advised to limit the number of treatment cycles they undergo, said van Leeuwen, head of the epidemiology department of the cancer institute.

The research looked at data from 25,152 Dutch women diagnosed with subfertility between 1980 and 1995. Of the 19,146 women in the treatment group included in the research, 31 had borderline ovarian cancer and 30 had invasive ovarian cancer. Of the 6,006 subfertile women who didn’t receive IVF treatment, 16 had ovarian malignancies.

The scientists plan further research on whether the number of IVF treatment cycles increases the risk of ovarian cancer.